The Institute for Electrical and Electronic Engineers (IEEE) standard 1394 (often referred to as “FireWire”) is a serial bus standard developed as an inexpensive alternative to parallel buses, which are confined to a small physical area, do not have plug-and-play support, and do not support isochronous applications. The standard is similar to the Universal Serial Bus (USB) standard available in most contemporary personal computers in that many devices connected via USB could alternatively be connected via IEEE 1394. If supported, IEEE 1394 could increase transfer rates, supporting transfer speeds up to 400 mega-bits per second (Mb/s) or greater for devices such as hard disk drives, motion video recorders, sound mixers and the like. Other advantageous features, such as a 16 exabyte theoretical address space, connection of up to 1024 buses each with as many as 64 devices to single computer, and support of scalability mechanisms such as hot-swapping and auto-detection or auto-discovery of connected/disconnected devices, make IEEE 1394 a versatile standard.
In order to use longer cables than specified by the standard, or to permit physical layers to have longer delays (e.g., arbitration gap delays) than the maximums allowed by the physical layer, a timing mechanism is required for determining, for instance, the bus arbitration gap count. There is, therefore, a need in the art for an accurate timing mechanism for evaluating IEEE 1394 bus delays.